1. Field of the Invention
This invention relates to a compressor inlet valve construction and, more specifically, such a valve wherein multiple functions are accomplished through a control tube which transmits fluid to the valve housing interior.
2. Description of the Prior Art
In connection with various types of compressor designs, a wide variety of valve constructions have been employed. See, for example, U.S. Pat. Nos. 2,241,195; 2,241,330; 3,348,764; 3,595,959 and 3,613,719.
In general, the prior art designs have been somewhat complex and frequently provide only a single purpose valve.
U.S. Pat. No. 2,241,195 discloses an unloading mechanism wherein a piston is adapted to contact a plunger which in turn operates through a spring biased spider-collar combination to move a poppet valve.
U.S. Pat. No. 2,241,330 discloses a fluid pressure operated valve arrangement which provides a number of clearance pockets in association with a compressor cylinder.
U.S. Pat. No. 3,348,764 discloses pressure equalizing means for a compressor wherein a gravity biased valve element is adapted, responsive to certain changes in pressure, to permit communication between the compressor inlet and outlet.
U.S. Pat. No. 3,593,959 discloses a pocket unloader valve wherein a piston is operated by pneumatic pressure introduced into the cylinder and overcomes the bias of a spiral spring so as to act upon the valve element.
U.S. Pat. No. 3,613,719 discloses a compressor valve wherein a hollow control piston is adapted to raise a valve plate through the lifting of interposed spheres.
There remains, therefore, a very real and substantial need for a compressor inlet valve which is of relatively simple construction and operation and will provide multiple functions.